Field of the Invention
The present invention relates to a slide cushion device of a press machine, and more particularly to a slide cushion device of a press machine, the slide cushion device pressing from above an area in a recessed portion of an upper die for a material to be press-formed.
Description of the Related Art
In recent years, forming of a high-tensile steel plate by using a press machine has become common, and a function of a slide (upper side) cushion that presses from above an area in a recessed portion of an upper die for the high-tensile steel plate during press forming is important to improve formability of the high-tensile steel plate.
Conventionally, there is provided a device for a press die that is to be used by being attached to a press machine, and that includes a work holding pad for holding a work, the work holding pad being movable up and down (refer to Japanese Patent Application Laid-Open No. 2006-061920 (Patent Literature 1)).
The device for a press die described in Patent Literature 1 is applicable to both a press machine with a cushion function and a press machine without the cushion function, and particularly in a case of a press machine with cushion means, the device includes a die body, a pad body attached to the die body so as to be detachable and movable up and down, and a pressing force transmitting rod that is provided in the pad body and a press machine side by penetrating through the die body.
The cushion means includes a base plate attached to a slide (ram) of the press machine, and a plurality of rod-less cylinders fitted into the base plate. The pressing force transmitting rod is attached at its one end to the pad body, and has the other end that is brought into contact with the rod-less cylinder of the cushion means, thereby transmitting pressing force to the pad body from the slide through the rod-less cylinder.
In an embodiment of Patent Literature 1, there is described the cushion means in which six rod-less cylinders are fitted into the base plate, the rod-less cylinders each being a gas enclosed type.
In addition, Patent Literature 1 describes the cushion means that is configured so that dies different in size can be attached to the cushion means (refer to FIGS. 15 and 16 in Patent Literature 1) to allow the cushion means to have versatility.